State-of-the-art digital communication switches, servers, and routers currently use multiple rows of duplex LC connector optical transceivers to meet information bandwidth and physical density needs. To be a commercially fungible product, the optical transceivers must have basic dimensions and mechanical functionality that conform to an industry standard Multi-Source Agreement (MSA) such as set forth in the Small Form Factor (SFF) committee's INF-8074i “SFP Transceiver” document. Many optical transceiver mechanical designs that comply with and add value beyond the basic mechanical functionally set forth in the MSA are possible.
FIG. 1 illustrates a standard configuration for a system 100 including an optical transceiver module 110 having a conventional delatch mechanism and a cage 120. Optical transceiver module 110 contains a transceiver that converts optical data signals received via an optical fiber (not shown) into electrical signals for an electrical switch (not shown) and converts electrical data signals from the switch into optical data signals for transmission. Cage 120 would typically be part of the switch and may be mounted in closely spaced rows above and below a printed circuit board.
When plugging module 110 into a switch, an operator slides module 110 into cage 120 until a post 114 on module 110 engages and lifts a latch tab 122 on cage 120. Module 110 then continues sliding into cage 120 until post 114 is even with a hole 124 in latch tab 122 at which point latch tab 122 springs down to latch module 110 in place with post 114 residing in hole 124. Post 114 is shaped such that an outward force on module 110 does not easily remove module 110 from cage 120. Module 110 has a delatch mechanism 130, which resides in a channel extending away from post 114. In a latched position, delatch mechanism 130 is outside cage 120, and post 114 is in hole 124. To remove module 110, delatch mechanism 130 is slid toward cage 120 until wedges 132 on delatch mechanism 130 slide under and lift latch tab 122 to a level above post 114. Module 110 can then be slid out and removed from cage 120.
Operation of delatch mechanism 130 can be awkward since removal of module 110 requires pushing in on delatch mechanism 130 while pulling out module 110. Additionally, when module 110 is in an array of modules in an optical switch, modules above module 110 will often block easy access to delatch mechanism 130, making removal of module 110 more difficult. Surrounding modules also make each module more difficult to grip.
Other module delatch mechanisms have been developed in attempts to simplify the removal procedure. One such module has a flexible strip that is attached to the module and resides under the latch tab in the latched position. To delatch the module, an operator pulls up and out on the flexible strip, and the flexible strip lifts the latch tab off the post on the module. Releasing the latch tab and removing the module in this manner requires significant upward force. For many operators, the operation of this delatch mechanism is not intuitive since pulling directly out on the flexible tab will not release the module. Additionally, in a high-density configuration, surrounding modules can make the flexible tab difficult to grip.
Another “pull-to-detach” mechanism provides the module with a post on a lever arm and a flexible handle mounted to a rod. When the flexible handle is pulled, the rod forces the lever arm to rotate and lower the post away from the cage, releasing the module from the latch on the cage. The pulling force on the flexible handle then slides the module out of the cage. Return springs that hold the lever arm and the post in position are features molded into the plastic housing. This system requires an operator to apply a great deal of force to remove the module.
FIGS. 2A and 2B illustrate cutaway bottom perspective views of a known optical transceiver module 210 having a delatch mechanism 230 that does not require excessive force to extract from a cage 120 and that is easily accessible in high density module arrangements. The module 210 and the delatch mechanism 230 are disclosed in U.S. Pat. No. 6,746,158 by the assignee of the present application and is incorporated herein by reference in its entirety.
In FIG. 2A, the delatch mechanism 230 is in a latched configuration. In FIG. 2B, the delatch mechanism 230 is in a delatched configuration. Half of cage 120 is cut away in FIGS. 2A and 2B to better show module 210, and the delatch mechanism 230, and part of module 210 is also cut away to better illustrate the delatch mechanism 230. Cage 120 includes a latch tab 122 (half of which is shown in FIG. 2A) including a hole 124 that can accommodate a post 214. Although FIG. 2A illustrates cage 120 as being isolated, cage 120 would typically be one of several substantially identical cages arranged in a dense array of cages. The delatch mechanism 230 includes an integrated structure 240 and a bail 250. Integrated structure 240 includes features such as ridges 242 and 244, spring arms 246, and wedges 248. Bail 250 is friction fit through a hole in integrated structure 240 and can be flipped down as shown in FIG. 2A to keep the bail 250 out of the way, or flipped up as shown in FIG. 2B to extend out and facilitate pulling on delatch mechanism 230 during removal of module 210. Ridges 242 and 244 also provide grip points for pulling delatch mechanism 230 when bail 250 is down or is otherwise inconvenient for gripping. An LC fiber connector (not shown) can attach to module 210 through the center of bail 250.
The spring arms 246 have ends in notches 216 in module 210. (The cut away view of FIG. 2A shows only one of notches 216, the other notch being omitted to better illustrate integrated structure 240.) The spring arms 246 flex in response to a pulling force on delatch mechanism 230 and permit a limited range of motion for delatch mechanism 230 relative to module 210. In the latched configuration shown in FIG. 2A, spring arms 246 can be uncompressed or have some spring loading, and wedges 248 reside in pockets 212 in module 210. Above wedges 248 is latch tab 122, half of which is illustrated in FIG. 2A. Through latch tab 122 is hole 124, in which post 214 resides when module 210 is latched in cage 120.
To remove the module 210 from the cage 120, an operator pulls out on delatch mechanism 230 via bail 250 or ridges 242 and/or 244. Initial pulling bends/flexes spring arms 246 and slides wedges 248 out of their respective pockets 212. As wedges 248 rise out of pockets 212, wedges 248 push up on latch tab 122. In FIG. 2B, the spring arms 246 have reached a limit of their compression and wedges 248 have lifted latch tab 122 above post 214. The spring arms 246 are at angles such that pulling on integrated structure 240 flexes spring arms 246 about their respective bases and extends the ends of spring arms 246 further into notches 216 in module 210. Accordingly, pulling more firmly engages spring arms 246 in notches 216. In the illustrated configuration of FIG. 2B, spring arms 246 contact fixed portions 247 of delatch mechanism 230 and cannot flex further. The pulling force thus acts on module 210 to slide module 210 out of cage 120.
Although the delatch mechanism 230 works well with regard to delatching and removing the module 210 from the cage 120, the delatch mechanism 230 does not work well for inserting the module 210 into the cage 120 to place the module in the latched configuration. To insert the module 210 into the cage 120, a user typically uses a finger to either push on the ridges 242/244 or on the extended bail 250 until the module 210 is latched within the cage 120 in the configuration shown in FIG. 2A. The module 110 shown in FIG. 1 is inserted into the cage 120 in a similar manner, except that it does not have a bail that can be used for this purpose. Rather, a user pushes on the front face of the module 110 to push the module 110 into the cage 120. As indicated above with reference to FIGS. 2A and 2B, there are typically many such cages 120 and modules 210 arranged in a densely packed array. In such arrangements, it can be difficult for a user to push with a finger on these features of the module due to the closeness of the modules within the array, which can prevent the user from having the direct manual access to the modules that is needed to push them into the cages. Although the extended bail 250 of the module 210 shown in FIGS. 2A and 2B can be used to push the module 210 into the cage 120, the bail 250 does not have the rigidness needed for this purpose due to the fact that it has a degree of rotational freedom of movement. Also, the bail 250 is too short to be used very effectively for this purpose.
Accordingly, a need exists for a delatch device that has a configuration that enables a user to easily push an optical transceiver module into a cage and thereby cause the module to be placed in the latched configuration. A need also exists for such a delatch device that also enables a user to easily place the module in the delatched configuration and remove the module from the cage.